This invention relates to water treatment devices, such as gravity-fed devices, and to filter cartridges used in such devices. In particular, this invention relates to a fill-counting cartridge and a cartridge assembly which removes water treatment particles from the treated water.
Domestic water treatment devices are known in the art. They include in-line devices (e.g., under the sink), terminal end devices (e.g., counter top or faucet mounted), and self-contained systems which process water in batches. Examples of batch devices are pitchers/carafes and larger reservoirs where treated water is poured for example from a spigot. Batch water treatment systems can also be incorporated into other devices, such as a coffee maker. These self-contained systems typically have upper and lower chambers separated by a filter cartridge. They rely on gravity to force water from the upper chamber, through the cartridge, and into the lower chamber, thereby producing treated water.
Mechanical filters, which treat water by preventing particulates from passing through them, provide a ready end-of-life indication through reduced flow due to particulate accumulation. Chemical removal media (e.g., charcoal based media and ion exchange media) employ processes such as adsorption and ion exchange for treating water. These processes do not reduce flow or provide other end-of-life indication.
Various approaches have been taken to provide end-of-life indication where it is not inherently provided by the media. It is known for example to xe2x80x9ctotalize,xe2x80x9d mechanically or electronically, the volume of water that has been treated. The mechanical approach typically involves a turbine and gear reduction mechanism. The electronic approach typically involves a pressure transducer and a microprocessor which integrates to calculate volume. Such systems are relatively expensive, however, and do not lend themselves well to batch treatment devices.
In batch treatment systems, it is known to approximate the amount of water that has been treated by counting the number of times the device has been filled. Such a prior art device is described in U.S. patent application Ser. No. 08/341,420, filed Nov. 17, 1994, which is expected to issue as a U.S. patent shortly. The ""341 fill-counting system employs a float which rotates one revolution on a threaded rod each time the device is filled. One short-coming of this approach is that there is no continuous visual indication of the amount of useful life remaining, but only an indication at the end of life.
Where relatively loose particle media are employed, such as the loose granular activated carbon and resins typically used in batch systems, media particles tend to come out of the cartridge with the treated water. Although ingesting these particles is generally not a significant health concern, consumers consider it undesirable to see what appears to be sediment in the treated water. An example of a gravity-fed system where this is a shortcoming is shown in U.S. Pat. No. 4,969,996.
What has been needed is a novel fill-counting mechanism which provides a continuous visual indication of the amount of useful life remaining in the filter cartridge. What has also been needed is a novel filter cartridge assembly which reduces the number of media particles in the treated water.
Certain aspects of this invention involve a filter cartridge end-of-life mechanism for a gravity-fed water treatment device. Although a carafe is shown herein, it will be understood that the invention could be employed in a variety of other gravity-fed devices, such as in a larger reservoir having a pour spigot or in a coffee machine.
In one aspect of the invention, the end-of-life mechanism comprises a float which rises when the water treatment device is filled, and falls after the water has been treated. A counting mechanism counts the number of times the water treatment device has been filled. The mechanism includes an escapement mechanism wherein the float is advanced along an escapement path each time the float rises and falls.
In another aspect of the invention, the end-of-life mechanism comprises a mechanism for counting the number of times the water treatment device has been filled. The fill-counting mechanism includes a member which is moved by the water. A visual indicating mechanism cooperates with the fill-counting mechanism to provide a continuous visual indication of the amount of useful life remaining in the filter cartridge.
In certain other aspects of the invention, the invention comprises a filter cartridge assembly which reduces water treatment particles in the treated water. Although a gravity-fed system is disclosed herein, the invention could also be employed in systems where the water is forced through the media by other than gravity.
In another aspect of the invention, the invention comprises a filter cartridge assembly for a water treatment device. The assembly includes a filter cartridge containing water treatment material and having an upper inlet end and a lower outlet end. A tray is positioned beneath the lower outlet end. It is detachably connected to the filter cartridge and separable from the water treatment device. The tray is constructed and arranged so that treated water flowing from the outlet end flows generally toward the inlet end and out of the tray. The tray holds particles of water treatment material coming from the outlet end, thereby making the treated water flowing out of the tray substantially free of the particles.